Automotive manufacturers have widely produced vehicles having engine cooling systems with viscous fan couplings for conserving engine power and enhancing overall vehicle performance.
Electrically actuated viscous-fluid fan couplings (“electrical fan couplings”) have been developed for providing a precisely controlled output, as determined by a vehicle engine computer. Specifically, the typical electrical fan coupling includes a viscous fluid, an operating chamber, a reservoir chamber, and a series of valve mechanisms actuated by the computer for metering the flow of viscous fluid between the operating chamber and the reservoir chamber. In this way, the computer can control the amount of fluid in the operating chamber and selectively engage the coupling for providing a predetermined amount of output.
Existing electrically-actuated viscous fan couplings include an actuator mounted to a rotating portion of the coupling through a ball bearing. Durability of this construction typically is a function of bearing life and tether life. Ideally, a fan coupling without a tether would be preferred if this improves durability and lowers cost while sustaining fan coupling performance attributes.
It would therefore be desirable to provide an improved coupling, particularly one having a robust construction and comprised of generally few parts with enhanced heat rejection.